The present invention generally relates to systems for replacing/changing lubricants in internal combustion engines. More specifically, the invention relates to systems for automatically or semiautomatically effecting such lubricant replacement/change.
It is well-known that the life of an engine can be greatly affected by the frequency with which the lubricants or oils thereof are replaced/changed. Engine life generally is increased with more frequent oil changes. Spent oil generally contains grit and other abrasive particles that cause undue engine wear and the removal of the spent oil reduces engine wear by removal of these abrasive particles.
Systems for replacing/changing the oil in an internal combustion engine are known. Typically, oil replacement systems include a new oil reservoir and a spent oil container coupled to the oil pan of an engine via appropriate valves and pumps. Generally, spent oil is expelled or pumped from the oil pan and then the oil pan is filled with new oil.
Several systems are claimed to perform this oil replacement/change automatically. One such system is a system disclosed in U.S. Pat. No. 3,447,636. The disclosed system includes a unit that is removably mountable in a motor vehicle that effects replacement of oil in the engine. The system connects to the electric supply system of the motor vehicle and, upon actuation of a switch, is stated to effect the replacement of the oil. An indicator lamp is employed to indicate oil replacement system operation.
Engine oil changes for a motor vehicle generally are determined by the mileage the vehicle has traveled since the last oil change. Oil changes for other engines can be determined by the amount of time the engines have been in operation since the last oil changes.
Both of these methods for determining when to change engine oil fail to fully account for actual engine wear. With respect to motor vehicles, engine wear can continue even though a motor vehicle is at rest. For example, an automobile engine idles and thus, continues to wear while the automobile is stopped such as at a stop light or moving slowly such as in a traffic jam. With respect to static engines, i.e., engines mounted at fixed locations, engine wear similarly varies depending on the loads placed thereon and the speeds at which they are run.